The compound 4-amino-6-t-butyl-3-methylthio-1,2,4-triazin-5-one is a commercial herbicide. It is made as disclosed generally in Westphal et al., U.S. Pat. No. 3,671,523, issued June 20, 1972, by reaction of methyl iodide with 4-amino-6-t-butyl-3-mercapto-1,2,4-triazin-5-one. The latter compound can be made, as also disclosed generally in U.S. Pat. No. 3,671,523, by reacting t-butylglyoxylic acid with thiocarbohydrazide. The t-butylglyoxylic acid is made by oxidation of pinacolone, which is costly on a manufacturing scale.
German Offenlegungsschrift No. 2,003,144, published July 29, 1971, discloses an alternative process for producing 4-amino-6-t-butyl-3-mercapto-1,2,4-triazin-5-one which can be represented as follows: ##EQU1##
The present invention provides another alternative route for producing 4-amino-6-t-butyl-3-mercapto-1,2,4-triazin-5-one.
One step of the process of this invention involves bromination or chlorination of 3,3-dimethylbutyric acid to produce novel 2,2-dihalo-3,3-dimethylbutyric acids. Bromination and chlorination of acetic and propionic acids are described in French Pat. No. 1,241,836 (1960) and British Pat. No. 752,761 (1956).